Conductive fluid pump



. 903 mum FIFSSGZ CONTROLLABLE J24 POWER SOURCE W. L. CARLSON, JR, ETAL CONDUCTIVE FLUID PUMP Flled Jan 16 1961 July 31, 1962 POWER SOURCE INVENTORS WILLIAM L.CA RLSON, JR.

RICHARD H. COLE BY ATTORNEY United ts 3,046,893 CONDUCTIVE FLUID PUMP William L. Carlson, Jr., Bloomington, and Richard H.

Cole, Crystal, Minn., assignors to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Filed Jan. 16, 1961, Ser. No. 83,002 5 Claims. (Cl. 103-1) The present invention is directed to a conductive fluid pump that utilizes two fluid pumping channels or conduits in the same magnetic structure, and is more specifically directed to a conductive fluid pump that is capable of be ing modulated due to a hydraulic circuit which incorporates the two conduits by the application of a small control flux.

The present invention utilizes the basic conductive fluid pump theory wherein a conductive fluid is caused to flow by an electric current and a magnetic field angularly disposed to each other and to the direction of flow of the fluid. This type of pump has been recognized for some time and is extensively used both for circulating large quantities of conductive fluids in coolant systems, as well as being used as a pressure source for electromagnetic hydraulic actuators. A typical electromagnetic hydraulic actuator to which the present pump could be applied is disclosed in U.S. Patent 2,948,118, to William L. Carlson, Jr. et al. The actuator utilizes two variable volume chambers with an electromagnetic conductive fluid pump between the chambers. The movement of fluid from a reservoir chamber into an output chamber provides for mechanical motion which can be applied to a device, such as a valve, as shown in Patent 2,948,118. Due to the nature of the electromagnetic conductive fluid pump, it is a difiicult pump to modulate with a relatively small quantity of electric power. The normal approaches to modulation are to vary the power supply to the pump over a full range of zero to maximum power thereby attaining a form of modulation. This type of modulation requires the control of a large amount of electrical energy and is an uneconomical manner of modulating an electromagnetic conductive fluid pump. Various other ways of modulating pumps are known but these again require substantial power changes in order to obtain the desired pressure changes.

In the present invention a simplified method of modulation of an electromagnetic conductive fluid pump is developed. This method of modulation utilizes two parallel electromagnetic conductive fluid pumps having common inlet means and common outlet means. The two electromagnetic conductive fluid pumps utilize a single magnetic structure and are of a type with a self-generated magnetic flux. The self-generated magnetic flux is combined with a flux generated by a control winding on a leg of the conductive fluid pump. The combination of fluxes in the unit provides for a gradual change in flux with a relatively small amount of input power to the control winding and this change in input flux changes the balance of pumping pressure in the two conductive fluid conduits. The conductive fluid conduits are connected in hydraulic parallel and are capable of having a varying output depending on the direction and amount of pressure in each of the conduits or output passages. The combination of the two hydraulic circuits in parallel allows for a single output that can be varied from a maximum with the two in parallel to a minimum when the two are operated to form a series circuit wherein the fluid is merely circulated around through the pump and is not supplied to the outlet of the pump in the conventional fashion.

It is a primary object of the present invention to disclose a novel conductive [fluid pump that utilizes parallel pumping channels to create a readily controllable output pressure.

It is a further object of the present invention to disclose a novel conductive fluid pump that can be modulated with a relatively small amount of control power to the input of the pump.

It is yet a further object of the novel pump disclosed herein to provide :a self-compensating conductive fluid pump that provides a self-generated flux which can be altered to control the pressure output of the pump.

A still further object of the present disclosure is to provide a novel conductive fluid pump unit which has a single magnetic structure for both the pump and the magnetic control circuit.

These and other objects will become apparent when the single disclosed drawing is considered with the following specification and claims.

The single drawing in the present application is an isometric view of a conductive fluid pump having two parallel pumping channels that have common inlet means and common outlet means.

The electromagnetic conductive fluid pump generally disclosed at 10 is formed in a magnetic core means having three parallel lugs 11, 12 and 13. The legs 11 and 13 each have a gap shown at 14 and 15. The gaps 14 and 15 provide an opening for the electromagnetic conductive fluid pump channels. The leg 12 is continuous Connecting an upper magnetic member 16 to the lower magnetic member 17 to complete the core structure. The core is preferably made up of a laminated magnetic material when the device is to be used on alternating current and can be made up of a solid magnetic material if the device is to be used on direct current. The details of the core construction are believed to be conventional and therefore warrant no further description.

A coil 20, which forms a flux generating means or the control winding for the unit, is placed around leg 12 and is shown in schematic form as a winding on a bobbin 21. Two conductors 22 and 23 connect to the coil 20 and lead to a controllable power source 24. The controllable power source supplies energization to coil 20 to supply a flux in the leg 12 which in turn branches into legs 11 and 13 depending upon the mode of operation of the device. This mode of operation will be explained in some detail after a complete description of the electromagnetic conductive fluid pump.

A hydraulic circuit having inlet means 25 and outlet means 26 has two parallel conduits or fluid paths 27 and 28. The conduits 27 and 28 are bridged by connecting members 30 and 31 in such a manner that fluid flowing into the inlet means 25 will split and flow through the member 30 into the conduits 27 and 28 and then combine in the member 31 to flow out of the outlet means 26. The proportion of fluid flow through each of the conduits 27 and 28 will depend on the amount of pres sure developed in each of the pumps formed in the present device, as will be presently described.

The branch or conduit 27 is flattened at 30 so as to form a rectangular cross section that passes through the gap 15. The flattened portion 30 is insulated either by an air gap or a fixed insulating material from the magnetic structure in order not to shunt any electrical current from the device if the hydraulic passage is made up of a high resistance metal, as opposed to being made up of an insulating material, as is done in some pumps. The flattened portion 30 has two electrodes 29 and 32 joined into the sides of the flattened portion so as to be capable of passing an electric current across the portion 30 in the air gap 15 through any conductive fluid that fills the hydraulic circuit or conduit 27. The conductive fluid most commonly used in a material which is a mixture of sodium and potassium. The present invention is not limited to this particular mixture but may be applied to any conductive fluid such as mercury, sodium, potassium, salt solutions, or even ionized gases. The current path between'electrodes 29 and 32 is at mutually right angles to the magnetic circuit formed by the leg 13 and the hydraulic circuit formed by the conduit 27. As is well known in the conductive fluid pump art, the existence of a magnetic field at right angles to a current will create a pumping pressure which is mutually perpendicular to the two generating forces. This hydraulic force will then move the conductive fluid along the conduit 27.

The electrodes 29 and 32 are connected to a pair of bus-bars 33 and 34. The bus-bar 33 connects to electrode 29 by passing into the magnetic structure of pump and then passing outwardly through conductor 35 through the gap to electrode 29. The current coming into bus-bar 33 then passes through the conductive fluid in the flattened portion 30 of the conduit 27 to the busbar 34. The bus-bars 33 and 34 are connected by condoctors 36 and 37 to a power source 40. It will be appreciated that the current flowing thus passes into the magnetic structure, through the structure to an electrode, and back across the magnetic structure so that a compensated conductive fluid pump is provided. The fact that the current flowing in conductors 36 and 37 along with bus-bars 33 and 34 completely links one leg of the pump 10 makes it obvious that a magnetic flux is generated in the leg 13 of the pump 10. This self-generated flux interacts with the current that generates it and provides a pumping pressure in a conventional fashion.

The pump structure passing through leg 11 is identical to that passing through leg 13 and is made up of busbars 41 and 42 which connect to electrodes 43 and 44. The electrode structure and the flattened conduit 45 are insulated either by air gaps or conventional insulating material from one another to prevent leakage paths for theflowing current. The bus 41 is connected by conductor 46 to the power source 40 while a conductor 47 connects the power source 40 to the bus-bar 42. Once again the current flow is from within the magnetic structure through the leg 11 and then back through the flattened portion 45 of the conduit 28 into the magnetic structure and back to conductor 46. This again provides a self-compensated electromagnetic conductive fluid pump in leg 11 and the flux for this pump is a self-generated flux.

Operation In describing the operation of the present device it is simplest to consider the unit as a direct current unit so that all of the currents and magnetic fields are stationary in space relationship and are in the proper phase relationship for the creation of a pumping pressure. The power source 40 supplies current to two electromagnetic conductive fluid pumps and these pumps have self-generated fluxes in the legs in which they pass in the overall magnetic structure. In each case the direction of cur rent from the power source 40 is such that the two pumps formed in conduits 27 and 28 pump in the same direction. That is, when the device is energized, pumping pressures exist in the conduits 27 and 28 which would cause a flow of fluid from the inlet means to the outlet means 26. With this particular arrangement of current flow, the self-generated magnetic flux in the legs 11 and 13 are as shown at 50 and 51. With no energy supplied by the controllable power source 24, the selfgenerated fluxes 50 and 51 would tend to flow around the magnetic core in the same direction. In this arrangement the flux 51 would tend to flow down in the center leg 12, while the flux 50 would tend to flow up in the same leg from its bottom. These two flux components generated by the two pumps in the outer legs would op- 4 pose each other thereby eliminating any flux flow in the leg 12.

If the controllable power source 24 is then energized it would generate a magnetic flux in leg 12 that would aid one of the fluxes 50 or 51 and partially cancel the other flux of 50 or 51. It thus becomes obvious that as the controllable power source 24 is increased in magnitude that the flux in one of the legs 11 and 13 is substantially increased while the flux in the remaining leg is decreased. Therefore one of the conductive fluid pumps 27 or 28 has an increasing pressure output while the other pump has a decreasing pressure output.

If the hydraulic circuit is now considered with the controllable power source 24 in an off condition, and the balance of the pump energized, it becomes obvious that two pumps are provided which are in hydraulic parallel and which are equal in pumping pressure. As such, a fixed pumping pressure will be developed between the inlet means 25 and the outlet means 26. By energizing the controllable power source 24, one ofthe pumps 27 or 28 is decreased while the other is increased. With two pumping sources in parallel relationship with one increasing and the other decreasing, a circulation of fluid will occur around the channel formed by the legs 27, 28, 30 and 31. This circulating hydraulic fluid then decreases the total amount of pressure available between the inlet means 25 and the outlet means 26. As the controllable power source 24 is increased in magnitude, the point is eventually reached wherein one of the pumps formed in legs 11 and '13 becomes completely ineffectual and the other pump becomes a maximum pumping source. The complete ineffectual pump forms a hydraulic short circuit in the device and the entire amount of fluid supplied to the device circulates around the closed loop and provides little or no pumping pressure between the inlet means 25 and the outlet means 26.

It thus become apparent that by increasing the power available from the controllable power source 24, it is possible to modulate the present device from a maximum power output to a minimum power output. The modulating hydraulic fluid pump that is supplied by the present device could be readily applied to the hydraulic actuator disclosed in the Carlson, Jr. et al. Patent No. 2,948,118 to position the valve shown in that patent in response to the degree of energization of the controllable power source 24.

The present pump has been described as operable on direct current and it is obvious that by application of the proper phased alternating current, the present pump would have the same novel characteristics. The single embodiment disclosed in the present application is illustrative of the principle of operation and is in no way intended as a disclosure of a sole embodiment possible of the present invention. Since one skilled in the conductive fluid pump art could readily convert the present invention into many embodiments the applicants wish to be limited in the scope of their invention only by the appended claims.

We claim as our invention:

1,. An electromagnetic conductive fluid pump filled with a conductive fluid: magnetic core means having a plurality of legs and two said legs having air gaps therein; fluid filled conduit means passing through each of said air gaps; said conduit means having common inlet means and common outlet means; electrode means including current source means connected to said conduit means at said air gaps; said electrode means positioned to pass currents through said conduit means at said gaps creating a pumping pressure in said conduit means at each air gap by interaction of said currents and a self-generated flux at each gap; and flux generating means associated with said core means and generating a magnetic control flux in said legs; said control flux combining with said self-generated flux to vary the pumping pressures in said conduit means; said pressures combining in said conduit means thereby varying the total outlet pressure available from said pump as said control flux varies.

2. An electromagnetic conductive fluid pump filled with a conductive fluid: magnetic core means having a plurality of legs and two said legs having air gaps therein; fluid filled conduit means passing through each of said air gaps; said conduit means having common inlet means and common outlet means; electrode means including current source means connected to said conduit means at said air gaps; said electrode means positioned to pass currents through said conduit means at said gaps so that said currents flow from within said core, through said conduit means and associated conductive fluid, and then back around said conduit means to a point within said core thereby creating a pumping pressure in said conduit means at each air gap by interaction of said currents and a self-generated flux at each gap; and flux generating means associated with said core means and generating a magnetic control flux in said legs; said control flux combining with said self-generated flux to vary the pumping pressures in said conduit means; said pressures combining in said conduit means thereby varying the total outlet pressure available from said pump as said control flux varies.

3. An electromagnetic conductive fluid pump filled with a conductive fluid: a magnetic core having three legs and two said legs having air gaps therein; a fluid filled conduit passing through each of said air gaps; said conduits having common inlet means and common outlet means; electrode means including current source means connected to said conduits at said air gaps; said electrode means positioned to pass currents through said conduits at said gaps so that said currents flow from within said core, through said conduits and associated conductive fluid, and then back around said conduits to a point within said core thereby creating a pumping pressure in each said conduit by interaction of said currents and a selfgenerated flux at each gap; and flux generating means associated with said third core leg and generating a magnetic control flux in said legs; said control flux combining with said self-generated flux to vary the pumping pressures in both said conduits; said pressures being capable of causing said conductive fluid to partially recirculate in said conduits, said inlet means, and said outlet means thereby varying the total outlet pressure available from said pump as said control flux varies.

4. An electromagnetic conductive fluid pump filled with a conductive fluid: a'magnetic core having three legs and two said legs having air gaps therein; a fluid filled conduit passing through each of said air gaps; said conduits having a common inlet and a common outlet; electrodes including current source means connected to said conduits at said air gaps; said electrodes positioned to pass currents through said conduits at said gaps creating a pumping pressure in each said conduit by interaction of said currents and a self-generated flux at each gap; and flux generating means associated with said third core leg and generating a magnetic control flux in said legs; said control flux combining with said self-generated flux to vary the pumping pressures in both said conduits; said pressures combining in said conduits thereby varying the total outlet pressure available from said pump as said control flux varies.

5. An electromagnetic conductive fluid pump filled with a conductive fluid: a magnetic core having three legs and two said legs having air gaps therein; a fluid filled conduit passing through each of said air gaps; said conduits having a common inlet and a common outlet; electrodes including a current source connected to said conduits at said air gaps; said electrodes positioned to pass currents through said conduits at said gaps so that said currents flow from within said core, through said conduits and associated conductive fluid, and then back around said conduits to a point within said core thereby creating a pumping pressure in each said conduit by interaction of said currents and a self-generated flux at each gap; flux generating means including a winding and a controllable power source; and said winding encircling said third core leg and generating a magnetic control flux in said legs in response to said power source; said control flux combining with said selfgenerated flux to vary the pumping pressures in both said conduits; said pressures being capable of causing said conductive fluid to partially recirculate in said conduits, said inlet and said outlet thereby varying the total outlet pressure available from said pump as said control flux varies.

References Cited in the file of this patent UNITED STATES PATENTS 

